The Effects of Roundup on Food Crops

By Sarah Metzker Erdemir ; Updated September 21, 2017

Roundup is the commercial name for Monsanto's glyphosate herbicide used on farms and in home gardens. Glyphosate is touted as a safe and environmentally friendly product because it is not a neurotoxin like many other organic phosphate herbicides, but it can have serious short-term and long-term health consequences to people, animals, and desirable plants. Roundup effectively kills any plant, so Monsanto engineers have had to develop genetically modified crops like corn and soybeans that are designed to withstand this herbicide.

Effects of Roundup

According to the label on Roundup, the product is highly toxic to people and animals in high doses. When the spray is inhaled, it can cause heart palpitations, coughing, and difficulty breathing. If swallowed, it causes severe gastrointestinal symptoms. The manufacturer recommends keeping Roundup off the skin and immediately changing and disposing of clothing that has had Roundup spilled on it because it can cause burning, rashes, numbness, and eczema. In the longer term, Roundup has been associated with salivary lesions and inflammation of the stomach lining. Agricultural workers who regularly come into contact with Roundup have reported pregnancy and fertility problems, and studies on laboratory animals have shown that glyphosate reduces male and female fertility and causes liver tumors.

Roundup & Food

The half-life of glyphosate in soil and water is up to 140 days, and residues have been found in soil as much as a year after application. Glyphosate residue remains in food products harvested from soil where it was applied and can even be measured in food that has been cooked. When sprayed, glyphosate can travel almost a mile and contaminate or damage nearby crops. The January 2009 issue of “Chemical Research in Toxicology” reported a study in which human umbilical, placental and embryonic cells were exposed to low doses of Roundup (similar to the amounts found in food residues). Within 24 hours of exposure, the cells were either dead or fatally damaged.

Roundup & Food Production

Roundup's short-term gains in food production often cause long-term problems that reduce overall production. Glyphosate is also toxic to earthworms and beneficial microbiotic life such as mycorrhizal fungi, which attach to plant roots and increase their efficiency at taking up water and nutrients, and Rhizobium bacteria, which fix nitrogen into the soil. Roundup can cause plant diseases like anthracnose and barley root-rot to become more virulent. The chemicals in Roundup (including the patent-protected surfactant used to help Roundup penetrate plant surfaces) have entered the food chain on all levels, from stock animals that eat GM crops to aquatic and other wildlife that are exposed to Roundup through their water and food supply.

Roundup Ready Crops

Roundup indiscriminately kills any plant it comes into contact with. For this reason, “Roundup Ready” corn, soybeans, sugar beets, and alfalfa (used in animal feed) are now grown throughout the world. These genetically modified (GM) plants don't die when hit with Roundup, allowing farmers to use even larger amounts of herbicides in their fields. Effects of these and other GM plants are becoming apparent because it is not possible to stop them from pollinating non-GM species and other wild plants. Farmers around the world have reported species of “superweeds,” or weeds that are apparently resistant to increasingly larger applications of Roundup because they now contain the Roundup Ready gene. The long-term dangers of GM foods in the human food supply are not well-known, but increasing concerns about the dangers of GM foods for humans and the environment have led the EU to heavily regulate these products.